So I have been reading various sources I have dug up on the internet regarding the use of Sulfite for the aforementioned silver-solvent property it provides when added in concentrations up to 100g/L. I also ran across discussion of using Borax as the alkali rather than Sodium Carbonate (washing soda).
In a discussion on Flickr, Molder2906 seems to have had very nice results using Caffenol C with Borax rather than washing soda. This makes some sense in light of Eirik Roberts’ reports about his Caffenol C-LS recipes (LS for low soda). He reduced the amount of alkali (decreasing the pH of his developer) and got reduced grain. It appears that lowering pH reduces the developer’s activity and thus results in “slower development” and apparenty finer grain.
Twenty Mule Team Borax is readily available, so I bought a box ($5.99 for four pounds of the stuff!)
My Sodium Sulfite arrived so I am going to attempt another head-to-head comparison between two developer recipes.
I will mix up 500ml of standard Caffenol C-L and 500ml of Caffenol-BS (that’s Borax and Sulfite…)
Here is the recipe for the first trial of Caffenol-BS:
Borax 40g/L
Sodium Sulfite 50g/L
Vitamin C 10g/L
KBr 1g/L
Instant Coffee 40g/L
A very nice reference paper on the chemical properties of Borax has been prepared by the Twenty Mule Team people.
I decided on 40g/L of Borax because it is a bit below the listed maximum solubility of Borax in water of 47g/L. Borax has a slightly lower pH (9.2) than washing soda (11.5). Borax is also a much more effective buffer than washing soda, meaning that the solution will stay at a constant pH as acid is added to (or removed from) the mix via the development process, solution oxidation, etc.
Borax is a good bit more difficult to dissolve compared to washing soda. I confirmed this fact just now as I mixed up my two developers. I think that using HOT water to make the developer will be the ticket. Then I’ll just let it cool for hours/days prior to use. This should be fine since the sulfite’s preservative action will keep it springtime fresh!
I had planned to shoot two rolls of film at a time with near-identical cameras, as I mentioned in my last post. I subsequently realized that this is totally unneccessary. I just shot one nice long roll of film in one camera and I’ll snip it in half when I load it onto reels. One half will be developed in each developer! Simple, simple, simple!
I have to run some errands for a few hours, so the developers will just have to sit for a while before I can dive in but it is going to be stand development for 60min @ 20º C.
Here are my two beakers, ready to roll:
A Shot Of Caffenol 